The Obama administration is stepping up its effort to combat childhood obesity, releasing new nutrition standards for foods sold outside of cafeterias in schools.

Under the new "Smart Snacks in School" standards, schools will be required to nix junk food and sugary drinks from vending machines and school stores, replacing those items with more healthful fare like granola bars, fruits, and lower-calorie beverages. The standards are intended to present school-age children with more "foods we should encourage," as the United States Department of Agriculture, which is responsible for implementing the new rules, phrased it in a press release. Specifically, that means more whole grains, fruits, and lean proteins in place of foods with high levels of fat, sugar, and sodium.

Eighteen percent of American children aged 6 to 11 were obese in 2010, up from 7 percent in 1980, according to the Centers for Disease Control and Prevention. Meanwhile, more than one-third of all children and adolescents were overweight or obese in 2010.

The administration's new rules for snacks come one year after the White House mandated that federally-subsidized school lunches and breakfasts be healthier. The new changes will go into effect starting with the 2014-15 school year, giving schools and vendors time to adapt.

The new rules are part of the Healthy and Hunger Free Kids Act of 2010, which Obama signed in 2010 with the help of a strong lobbying effort from First Lady Michele Obama. The first lady, who has championed efforts to promote healthy lifestyles in children and young adults in the past, framed the new guidelines as an assist to busy parents like herself.

Many parents are working hard every day to make sure they provide healthy, balanced meals and snacks to their kids. Unfortunately, we don't always have control over the snacks our kids have access to when they're away from home. That's why, as a mom myself, I am so excited that schools will now be offering healthier choices to students and reinforcing the work we do at home to help our kids stay healthy. [White House]

Critics have decried those efforts as evidence that the federal government is an out-of-control nanny state. In one memorable incident, Sarah Palin protested efforts by Pennsylvania school officials to implement similar statewide guidelines there by bringing hundreds of cookies to one school's bake sale.

The USDA released the following infographic breaking down what will happen to school snacks under the new guidelines: